Gray mottling of new surface-not enough brushing?

[Phakur]

Okay--I have read all I can regarding the gray mottling that occurs sometimes after re-plastering. The mottling is extremely hard and will not come off with a diamond pad. All the sites state that it is caused by either dry troweling or by calcium chloride in the mix.

I presented all this information to the refinisher and he has stated that all of that is not correct and this mottling is caused by not enough brushing after the pool was re-filled. He knows that the brushing was intermittent (because I was unfortunately hospitalized and then laid up away from home for about 6 weeks) right after refinishing. Actually it was brushed about once per week ( I think, because I hired a pool guy to do it and I cannot confirm what he actually did).

So my first question is, is it possible that poor or intermittent brushing would cause gray mottling of a new plaster surface? Either way though, it looks like I will have to live with this or refinish.

Second question is in regard to new finish over this finish? Do I have to chip out this plaster in order to assure it doesn't show through?

Thanks.

Larry